build: Put all binaries into `bin`-subdir

hax: build-hax_read build-hax_exec build-set_cr

build:

	mkdir build

bin:

	mkdir bin

build/%.o: src/%.c build

%.o: src/%.c

	gcc -o $@ -c $<

build-%: build/%.o

	gcc -o $* $?

build-%: %.o bin

	gcc -o bin/$* $<